Pitman



Mays, 1930. w WTCHELL ET-AL `1,757,25s

M ay 6, 1930. MITCHELL ET AL PITMAN TORNEYS.

Patented May 6, 1930 N UNITED STATES ',PATENTfoFFICE MARION, INDIANA, ASSIGNORS-TO MARION MACHINE FOUNDRY & SUPPLY COM- PANY, OF MARION, INDIANA, A CORPORATION t f A HTMAN Application led, October `3, 1927; Serial No.` 223,802.

This invention relates toa pitman construction peculiarly adapted for use in oil andoth'- er well drilling machines and particularly be#Y use of a steel pitman, and the usualvsteel pit-` man has rigid bearings for the wrist pin, and since the machinery of a drilling rig is not accuratelyY lined up, the pitman is usually out of line with the pin especially when under load, and has this position when the load is reduced, as on the downward stroke ofthe tools. This has a tendency to bend the wrist pin and finally break it. Also it causes the bearings to heat excessively and cut the bear-v 'ing metal` and also score the wrist'pin.

The objectof this Vinvention is Vto overcome the foregoingv trouble and the chief feature of the inventionfor accomplishing said object consists in the'provision of a pivoted bearing which is free to oscillate in the pitman and which permits the bearing to be in proper alignment with the wrist pin at all times. e

The full nature of the invention will be understood fromV the accompanying drawings and the following description and claims: VIn the drawings Fig. 1 is aside elevation of.

the pitman constituting this invention `and parts associated therewith, said parts being partlyV broken away. Fig. 2`is an enlarged perspective view ofthe lower. portioneof the pitman shown in Fig. 1 with the parts larranged in working position. i Fig. 3 is a view similar to that shown in Fig. 2 with the parts of the pitman in their positions during re* moval from the wrist pin or when not on the wrist pin.

Fig. 4 is a central vertical section through the portion of the pitman as shown,v in Fig. 2; Fig. 5 is a central vert-ical section of the porling the latter.

tion of the pitman as'shown in Fig. 3. Fig. 6 is an elevation of apart of the pitman with the lower bearing being removed, and other parts omitted.` e

There is shown herein an end of a walking beam of the usual form found in drilling rigs for oil wells. It is operatively connected by the pitman 11 with the wrist pin'12 ad-l justably mountedon'the crank 130fthe shaft 14. The lcrank shaft 1 4 is mounted in bearings 15 on supports 16 extending up'from beam` 17. The power is thus transmitted through -thepitman from crank shaft 14 to the walking beam for the purpose of operat- The pitmanfincludes a bar in the form of an I-beam to the upper end of which there is secured a stirrup 2l which extends over the end of the walking beaml andis secured lin operating connection therewith by the usual means.' t

yTo thelowerend of the bar 20 there is se- `cured 4a yoke 25 in which the-bearing of the pitmanis mounted." This yoke is a vU-shaped plate having in one side a slot 26 and in the other side and opposite the lower kportion of the slot26 there is a hole 27.v The slot 26 and Vhole 27 receive the gudgeons 28 and 29 respectively, of the lower bearing member 30 for the wrist pin 12. These gudgeons are round and extend transversely of the wrist vpin so asto permit rocking movement to the earing member 30, and an oil cup31 is removably secured to the Vgudgeon28. The upper bearing member'or cap 32 is lmounted on the lower endof the* rod 33 by means of a plate .34. Said rod extends through ariopening 35 into plate 34 and has on it a semi-spherical head 36 which lies and operates in Va chamber 37 in the upper part of the bearing'member 3 2, asV indicated inV Figs. 4 and' 5.V The spherical surface of said head engages the upper bearing member at the lower wall or surface of the chamber 30, asshown in Fig'. 4 and rocks thereon during any oscillation of the rod 33. The upper surfaceofthe head 36 is'bevelled away so 'as to make the head slightly lessfthan semi-spherical and thereby` permit the rocking movement of the chamber head in the chamberBO and yet hold the head snugly between the upper plate 34 andthe lower wall 37 of the bearing 33 so that there will be no loss of power or play between the bearing and the rod 33.

Therod 334is threaded. at its upper end into ani eccentric' strap 4:0.Y Therefore", the unit composed of the rod 33 and the eccentric strap 40 is adjustable in length and itis pivotally mounted omaniece'emnie mithatfismountedion aYpmLL/Qiifiayokeiiloriginallyisecuredi to the I-beam 20. A hand lever 44 is rigidly? secured to the eccentric 41 and the eccentric is so arranged that when said hand leven-is* turned downward againstV the VLb eam, as shown in Figs. 2 and; tile eccentric' would forcefV the rodz33r downward i and, through it, the cap bearing membery 32- wouldfibey forced downwardr to .close.the bearings. on vthe 'wrist pin, as shown in Fig; l, and thisisfthevcondition vduring;operatien .offthemachinaH f VVfhenY itI isT desired to ,removes thepitinan from .the lwristlpirnljthe h and leverlg .isvturned unwardlto theposition :shown in Figs..z 3' and 'lwliichhwouldfcause the eccentric tcffrais'e therod33 and notfonly-release-the cap bear ing,32`. butllift.. it 4away;Lv from fthe, lowerfbear; ingzmemb'er, as, shown Eig. 3rwhichf would enablethe yft'obe rmoved laiterallyeo ofand. awayfrom.thewristflainl Since the rodV 33, which may Fble-called the bearingcontrolling rodr is such that its length can :be :'adjusted', ,it isso adiustedgthaa, the hand leveris down. in thepositionshown in FigsnQl andi4the top bearing memberr33 to resist the upper thrustwithoutany-dis placement. i

By reason of the s101126, theglowerf bearing. member=30 canbe easifly tilted outofitsfseat and entirelyreir-loved#l if desired` and i a new one replaced, in. itssteadf, ,Roelf ,33 is guided aecuratelyfby aplafte() wiiiclihasrcentrally in# it a hole 51` that Vfitsrrthe. rod'fso-asitox per-- Initf its slightoscillatorymovemem,v aalseen in Figs. 3. and Land yet :hold it rather closely nxposition. c' Saidlplate =ff-has-twofflateral holes ,52"in registryfwith. the-nuts` 53 :so that A JC lieywill not strike theplate. 50; There-are handles 52h52 and. ,55 lon the frame. Ilierefv -is also. a strap,A 56 thebottolnsforfthe rpurpose offsltpportingzg the handlel` and strengthen! ingfthe sides o'fzbearingjyolce.-

It ris .evidentr from 'the eregoingenplanzt tion thatlthebearingaforgftheflwristfrpin roel; or .oscillateI iso-:accommodate fit tienfofgiftl'iewrist andgtefbe in 'proper .aliign` ment a t herewithi- This? is.zfdesirablebecause the p ineis-.not falwayshorizontal fbutvaef riestofdierent slightfdegrees iromwthehor# iiontal positibn l afndlthe chieffobjeetvottheg inventionis .to`4 enable .thebearing to `faceom+- modateyits elfiz'ftoL the different positiensolthe wristfpinfso; as toenabletlie Wristfpinfto fb'eaxr eqjuallyfon qtlreiisuraeesiofethef bea-ring! awaysmaintn the desiredfal'ginnentr.

It is also seen that thereis a very convenient' and quickly operated means'for releasing the bearing members and removing the pit-y o.

:secured thereto, saidfyolie-iliavingi bearing openingsinltliefopposite sides`- thereof,- aj main wrstpin-'ibearingnernber 'having Vro`u1'd`gud geons on the opposite ends thereof and eX- 4tending transversely of the wrist pin 'and litting in said openings, a companion bearing f member' in 'saidiyoke,"and means for holding main-bearing. member, vsaidineans being loosely' connected/with ,said companion member i sotliat thefmainfbearing member may-*rock toV accommodate itselfto vthe wrist pin.

2; -Apitman-v including -aibar having a yoke secured-atheretoysaid. yoke"V heaving;bearing` f openings in the opposite sides thereof, one ol which iselongatedl longitudinally vto i form al slot, afma-ini wristzpin bearing member havinvsgudgeons ittingfinsaidfopeningsinsaid y ie, a companion bearing: member' in said yoke', a rod loosely;connectedr with sai'dfcom'- panden bearingimember, means for mounting sa-idrrod: onwsaid lbar, A and 'means/1forlongitudin-ally moving the rod and, companionbeari-f nginemberto cause thelatter to engage with. the main` bearing. member: and-,moveawayfromsaidfmainbearingimemberto'render the Y bearing: :membersF removabiei= fr substantiallyf-a-'sshowinV i Y 3.'A pitmansubstantiafllyasvset forth in claim 2, witlrztherodfforholding andmoving f said :bearing: member having. a.' rounded .head for engaging the upper surface' o-:t'saidccm"` panon bearing member, .and-capfseeured `to thenipper surfaceioffsaid companionbearing member andsur/rounding" th'ef'saidfrod and forming;aichambertherein? fort-he headf'on the rod', wherel` yA the':=b'e'aring. members may rock when: .heldfl tightly htogetheruzmd fsaid bearing members frnay be separated l'by the retraction c SO saidcompanionbearlngrmember against said 

